A Compact Wideband Circularly Polarized Implantable Antenna for Cardiac Pacemaker Devices

We propose a novel compact circularly polarized implantable antenna working at the Medical Implant Communications Service (MICS) band (400 MHz). The proposed antenna has a small overall size of 4.6 × 5 mm
²
. It consists of a truncated patch to ensure the circular polarization combined with a spiral shape to guarantee miniaturization. This technique allows a broader impedance matching of 39.89 % between 307 and 460 MHz and a wider axial ratio (AR) of 17.82 % from 368 to 440 MHz. Moreover, the antenna has the advantage of simple fabrication process without any defective ground plane nor shorting pins inclusion. Finally, compared to the state-of-art, the proposed design has the smallest size and broader AR making it a good candidate for pacemaker devices.